Emission control device for carburetor-equipped internal-combustion engines

ABSTRACT

An eccentrically pivoted control vane is provided in a bore interconnecting a standard carburetor with the intake manifold of an internal-combustion engine. The shaft of the control vane is connected to a pressure sensitive actuator exposed to the differential between atmospheric and induction manifold pressure levels; the angular position of the control vane being, therefore, sensitive to both engine air mass flow and manifold vacuum. Two inlet ports, for diluting air and recirculating exhaust gas, variably obscured by tabs mounted on the control vane, flow through them depending on the angular position of the latter. A secondary air dilution circuit provides a small flow of air at intermediate manifold vacuum conditions. Emission of harmful pollutants is substantially reduced by the admixture of recycled exhaust gas and of diluting air with the engine propellant charge.

United States Patent [191 Bohls et al.

[4 1 Jan. 22, 1974 EMISSION CONTROL DEVICE FOR CARBURETOR-EQUIPPED INTERNAL-COMBUSTION ENGINES [76] Inventors: Victor C. Bohls, 6391 Brittany PL,

Littleton; D. Douglas Graham, 2000 W. 92nd Ave., Denver, both of C010.

[22] Filed: Feb. 7, 1972 [21] Appl. No.: 223,863

[52] US. Cl. 123/119 A, 60/278 [51] Int. Cl..... F02b 33/00 [58] Field of Search 123/119 A; 60/278, 279

[56] References Cited UNITED STATES PATENTS 3,237,615 3/1966 Daigh 123/119 A 3,294,073 12/1966 Bressan 123/119 A 3,368,345 2/1968 Walker 60/278 3,542,004 11/1970 Cornelius 123/119 A 3,610,219 10/1971 Sciabica 123/119 A 3,641,989 2/1972 Hill 123/119 A 3,643,641 2/1972 Busse.... 123/119 A 3,646,923 3/1972 Sarto 123/119 A 2,154,417 4/1939 Anderson 123/119 A Primary Examiner-C. J. Husar Attorney, Agent, or FirmBurton L. Lilling; James E. Siegel; Henry A. Marzullo, Jr.

[5 7] ABSTRACT An eccentrically pivoted control vane is provided in a bore interconnecting a standard carburetor with the intake manifold of an intemal-combustion engine. The shaft of the control vane is connected to a pressure sensitive actuator exposed to the difierential between atmospheric and induction manifold pressure levels; the angular position of the control vane being, therefore, sensitive to both engine air mass flow and manifold vacuum. Two inlet ports, for diluting air and recirculating exhaust gas, variably obscured by tabs mounted on the control vane, flow through them depending on the angular position of the latter. A secondary air dilution circuit provides a small flow of air at intermediate manifold vacuum conditions. Emission of harmful pollutants is substantially reduced by the admixture of recycled exhaust gas and of diluting air with the engine propellant charge.

9 Claims, 11 Drawing Figures PATENTEDmze m4 3,786,793

sum 1 as PATENTEDmzz m4 3 786, 793

sum or /6/ WW 2 W EMISSION CONTROL DEVICE FOR CARBURETOR-EQUIPPED INTERNAL-COMBUSTION ENGINES BACKGROUND OF THE INVENTION The present invention relates to devices for the control of polluting emissions from internal combustion engines. It relates, more particularly, to such devices for carburetted engines operating on gasoline fuels in which a proportion of the exhaust products of the engine is recirculated to the intake manifold.

The Otto-cycle, gasoline fueled,'internal combustion engine is a light-weight powerplant whose advantages have led to its adoption for the propulsion of many vehicles, such as automobiles, motorcycles and motorboats; its greatest drawback, the relatively large emission of harmful chemicals in the engine exhaust was not generally recognized .until recently.

As a result of extensive investigations it has been determined that three components of the exhaust stream, unburned hydrocarbon fuel, carbon monoxide and the various oxides of nitrogen, have the most deleterious effect on the environment. Laws to control such emissions have been passed and created a demand for devices which would help to reduce the emission of these pollutants to acceptable levels.

Harmful emissions may be reduced by ensuring more complete combustion in the engine and the avoidance of operating conditions tending to promote the formation of nitrogen oxides; these results may be attained by providing leaner fuel mixtures, the admixture of exhaust gas with the fuel/air mixture entering the engine, or by secondary combustors in the exhaust system.

Many devices to accomplish these ends, sometimes in combination, have been proposed in the prior art. Such devices are generally cumbersome and require that some of the basic components of the conventional internal combustion engine be substantially redesigned or modified, or, alternately, they call for the addition of bulky and expensive components air pumps and catalytic reactors are examples to the basic engine.

The instant invention aims at accomplishing the reduction of harmful pollutants by the provision of a very simple device, incorporating control valves for the regulated admission of filtered air and exhaust gas to the intake stream, which does not require modification of any part or accessory of the engine.

It is a primary objective of the invention to teach the construction of a simple emission control device.

It is a further objective of the invention to define embodiments of the aforementioned emission control device which are self-contained and readily installed on existing engines.

It is yet another objective of the invention to teach the construction of emission control devices which are economical to produce, easy to install, and whose use results in a minimal reduction in the performance of the engine and, hence, in the driveability of the vehicle it powers.

SUMMARY The objectives of the invention are accomplished by the provision of a control body between the carburetor and the intake manifold of the engine whose harmful emissions are to be moderated. Passages through the control body correspond in number, size and location to the intake passages of the carburetor. Located in these passages are eccentrically pivoted control vanes, one in each passage, whose angularposition is jointly governed by the volume flow of air/fuel mixture from the carburetor and the manifold vacuum. The position of the vanes, in turn, regulates the admission of additional atmospheric air and of exhaust gas into the intake stream. By suitable combinations of vane size, pivot offset, return-spring load and vacuum sensor load, any desired relationship between vane position and operating parameters such as engine speed and vehicle power demand may be generated.

The admission ports for diluting air and exhaust recirculation terminate in tubular stubs within the central passage, or passages, of the emission control device; the flow through the ports being regulated by tabs attached to the corresponding control vane; the tabs, in sweeping past the open ends of the stubs, vary the obstruction to the flow of these gases from a completely open to a completely closed position.

The control functions for flow through the dilution ports are readily altered by the choice of placement of the regulating tabs, their size and shape, with control vane position as the governing factor.

It is readily appreciated that the emission control device of the invention, being controlled by sensors responsive to the flow conditions in the intake manifold, is completely independent of the engine controls; requiring no mechanical connection to the accelerator pedal, for example. Only supplies of filtered air and en gine exhaust gas are required and, as will become clear from the detailed description of the preferred embodiment, in many instances these connections may be made without recourse to external piping.

While many additional advantages of the invention will be apparent to one skilled in the art, after exposure to the teachings of the disclosure below, the greatest advantage resides in the ability of a controller constructed according to the invention to reduce the hamful emissions of an internal combustion engine by the simple installation of an auxiliary control plate between the carburetor and the intake manifold, without any modification in the engine or in the carburetor.

DESCRIPTION OF THE ACCOMPANYING DRAWINGS The preferred embodiment of the invention is illustrated and discussed with reference to the accompanying drawings, in which:

FIG. 1 is a side-view of an internal combustion engine fitted with an emission control device of the invention;

FIG. 2 is a frontal view of the same engine;

FIG. 3 is a view from above of the preferred embodiment of the emission control device, adapted to be used with a two-barrel carburetor;

FIGS. 4 and 5 are side and bottom views, respectively, of the device of FIG. 3;

FIG. 6 is a sectioned view, taken along line 66 of FIG. 3, of the preferred embodiment, showing the control vane and its integral tabs;

FIG. 7 is a frontal section of the device, taken along the centerline of the vane pivot-shaft;

FIG. 8 is a section in plan-view of the device, taken along line 8-8 of FIG. 4;

FIG. 9 is another section of the device with the moving parts omitted;

FIG. and FIG. 11 are additional sections of the preferred embodiment illustrating specific features of its construction.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention will be described in detail with reference to the illustrated embodiment which is adapted for use on a V8 engine, as widely employed in automobiles. These engines are normally supplied with twin carburetors in a common housing, generally referred to as a twin-barrel unit. In no sense is a limitation of the invention to a two-barrel device intended; embodiments with a single air passage adapted to the carburetors commonly employed with four and six cylinder engines or with four such passages to fit the quadruple units often used in high-performance V-8 engines are equally comprehended.

Turning to FIGS. 1 and 2 in the drawings, there is shown a V-8 engine 100 with two four-cylinder banks disposed at 90 relative one to another, and the usual accessories; an air-filter 110 surmounting a carburetor 1 atop intake manifold 130, a fuel pump 120, and the fuel-line 121 interconnecting the fuel pump and carburetor 1, and the exhaust manifold 140. An emission control device 3 of the invention is interposed between the carburetor 1 and the intake manifold 130 and a dilution-air transfer tube 111 leads from the air-filter 110 to the device 3. No channel for exhaust gases is shown between the exhaust manifold and the emission control device, such channels are generally provided on engines of this type in the intake manifold casting and terminate under the carburetor baseplate. The function of these passages is, generally, to provide heating to the carburetor in cold weather. It is also known to provide combination intake and exhaust manifolds in which such passages, known as exhaust cross-overs, are integral with the manifold body.

FIG. 3 is a view of the top surface of the emission control device 3, side and bottom views being provided in FIGS. 4 and 5, respectively.

The device 3 is provided with a housing 30 in the form of a flat plate, approximately one inch in height, pierced by induction passages 32 whose cross-section and location correspond to the discharge orifices of the carburetor l. A number of bolt holes 31 are also machined through the body 30, they, in turn, correspond to the holes in the carburetor baseplate through which the latter is mounted to the intake manifold.

Flow of the fuel/air mixture produced in the carburetor l is downward through the bores 32 of the device, past control vanes 40 which are mounted in a shaft 35 offset from the centerline of the passages 32. The flow of intake mixture tends to rotate the vanes 40 into the open position, aligned with the axis of the passages 32, a tendency resisted by the spring action of the diaphragm in the vacuum-sensitive actuator 60.

The actuator 60 is mounted to the main body of the device 3 by means of a sheet-metal bracket 63 and is connected to the vane-shaft 35 by means of a push-rod 61 acting on a crank 62; the latter being fixed on the shaft 35. One face of the actuators diaphragm is exposed to atmospheric pressure, the other is in communication, via the flexible conduit 161, with the bores 32 of the device; thereby experiencing intake manifold pressure. When the depression in the intake manifold is high, the actuator tends to rotate the control vanes 40 into a position blocking the passages 32. The null position of the vanes is adjustable by suitable clamp means incorporated in the crank 62, it is generally set to partially open the passages 32 with the engine stopped; the vanes will tend to rotate from the null position in a direction depending on the prevailing balance between the drag forces exerted by the intake stream and the pressure differential experienced by the actuator 60.

The bottom view of FIG. 5, in conjunction with the sectioned view of FIG. 6, will be used to explain the manner in which the diluting air and exhaust gas streams are admitted into the intake manifold.

The particular emission control device 3 is intended for use with an intake manifold incorporating passages for exhaust gas terminating at the carburetor mounting face. With the device body 30 interposed between the intake manifold 130 and the carburetor, these exhaust passages are open to the milled pockets of the device, and the latter are in communication with nozzles 71 intruding into the bores 32. Control tabs 41, integral with the control vanes 40, are so arranged that, in the closed position of the control vane, the open end of the nozzle 71 is completely obscured by the appropriate tab 41, thereby interdicting the flow of exhaust gas from the manifold passages into the intake stream. As the control vane 40 rotates from its closed position toward the fully open one, the tab 41 is carried away from the mouth of the nozzle 71 and permits an increasing flow to pass from the exhaust manifold into the intake manifold, impelled by the pressure differential naturally existing between these two spaces.

Filtered atmospheric air is supplied to the device, for purposes of diluting the intake stream, via the transfer tube 111, to the fitting 50 and, thence, through air passages 51 drilled into the device body 30, to nozzles 52. The function of the nozzles 52 and the co-operating tabs 42 is analogous to the corresponding components in the exhaust gas circuit. In the closed position of the control vane 40 the admission of air is suppressed by the tab 42, in the open position of the vane it is unobstructed and the diluting air flow is proportional to the flow through the carburetor 1.

The sectional view of FIG. 7 shows necked-down portions 36 on the vane-shaft 35, permitting the diluting air passages 51 to lie in the same plane, and to cross, the orifice 39 in which the vane-shaft rotates. Another constructional feature of the shaft 35 is the axial slot 37 over that portion of the shaft intercepting the induction passages 32; the vanes 40 are mounted in the shaft after insertion through the slot 37.

FIG. 8 is yet another section through the pollution control device 3, illustrating with particular clarity a secondary dilution circuit controlled by a needle-valve 91 and suitable plugs 59 for the passages in place. The fitting 50 terminates, on its inboard bore, in a conical seat 55 whose surface is parallel to the head of adjusting screw 90. The adjuster is threaded into the body 30 coaxially with the socket of the fitting 50 and may be positioned relative to the conical seat 55 in the fitting by means of a screwdriver inserted through the bore of the latter. Turning the screwdriver counterclockwise results in narrowing the passage between the seat 55 and the adjuster 90, thereby restricting the flow of diluting air; turning it clockwise has the opposite result.

95 on the farside of theinsert 94on the othenAspring 93, biasing the needle-valve into engagement with the orifice the adjuster 90 is also provided. I

' Under/high manifoldiv'acuuimconditions an unbalanced pressure force acts on the valve .9 1, tending to pull it away from its seat, a tendency resisted by the spring'93, establishing a' balanced position-which permits a certain, but'low, flow of air past-the needle-valve into the main intake passages. 'As the intake manifold vacuum increases,-the needle-.valve-91-mov es further toward the insert 94 until, at extreme'vacuum ]evels,its

lower end blocks the orifice therethrough and cuts off the secondary dilution flow. The secondary, or compensating, circuitiprovides,therefore,"a small amount of diluting air at intermediatefnianifold pressures; the

' orifice I62'communicates with the tubel6l by means of a coupling 163 rigidly held .in the device body 30, and providestheworkingsignal to actuator 60.

- The embodiment described above is basically a retrofit device for installation on motor vehicles originally produced without significant emission control equipment; it is'installed-in a vehicle byre'moving the carburetorfromthe engine,fplacing the control device said carburetor.

with appropriate gaskets -on the carburetor mount:

in'g pad and reinstalling thecarburetorfwhile'"minor changes in the carburetor settings, in" carburetor linkage connections, and in'the settings ofthe control device air dilution circuit may be performed at this time, such adjustmentsare not always required. The vehicle may be operated, after connecting an air supply hose from the air-filter to the fitting 50, normally and will show a substantial reduction in all three classes: of harmful emissions; unburned hydrocarbons, carbon monoxide and nitrogen oxides,

In a modified embodiment, the hose lll connecting the device air circuit to the air-filter may be omitted, by providing a small air filter integral with the fitting 50.

In engines in whichthe carburetor mounting pad is embodiments and applications of the invention willsuggest themselves without departing from the scope of the invention. The disclosures and description herein are purelyv illustrative and not intended tobe in any 6, sense limitinggThus, for example, the device need not necessarily take the above described fonn and the inventioncould be applied equally as well as simply being made a part of or integral with either the carburetor or the intake manifold.

What isjclair ne d is; H I A .l. A device for the reduction of polluting emissions from, an internal combustionv engine having a carburetor and intake manifold, said device comprising: a

body; at leastoneinduction passage through said body,

interconnecting said carburetor with said intake manifold; eccentrically pivoted vane means in said induction passage; first and second nozzle means communicating with said induction passages; first conduit means, interconnecting; said exhaust manifold of said engine with said first nozzlerneans; second conduit means, interconnecting saidlsecond nozzle means with the atmosphere; first and second tab means, rigidly attached to said vane means, for variably obstructing discharge orificesof said first and second nozzle"means,'respectively; and actuator means, linked to said vane means, for pivoting same in response. to flow parameters or conditions of gases through said induction passage, whereby said first arid'second tab-means-govem variable flow' of recirculating exhaust gas and atmospheric dilution air through said first and second nozzle means. 2. The device according to claim '1, wherein said body is provided with a plurality of induction passages, said induction passages being equal in number, and in communication with,. multiple induction channels in 3; The device according to claim 1, wherein said actuator means including-a positionersensitive to pressure differential between atmosphere and induction manifold. l

. 4. The device according to claim 3, wherein said vane means cooperates with-said actuator meansin'positioning said tab means in'response 'to velocity of gases in said induction passage. v

5. The device according to claim 3, wherein said positioner comprises: a hollow chamber; a flexible diaphram partitioning said chamber intofirst and second spaces; channel means interconnecting said first space with said induction passage; orifice'm'eansinterconnecting said second space? with atmosphere; shaft means, rotatably located in said bodyjfor' eccentrically 6. The device definedin claim 2, for use with engines equipped with twin-barrel carburetors, wherein said induction passages number two.

0- 6 I second nozzle means including at least one tubular 7. The device according to claim 1, wherein said first nozzle means including at least one tubular channel intruding into each'of said induction passages, and said 1 channel intruding into each of said induction passages.

8. The device according to claim 1, further comprising: third nozzle means communicating with said induction passages; third conduit means, interconnecting said third nozzle means with atmosphere; and governing means', sensitive to differential in pressure between atmosphere and gases flowing through said induction passages, for controlling the flow of additional diluting air into said induction passages.

9. As an article of commerce, a device for interposition between a carburetor and the intake manifold of an internal combustion engine, said device incorporating means for the reduction of harmful emissions from the exhaust manifold of the engine, comprising; a substantially rectangular body; at least one induction passage through said body, or said passage, or passages, corresponding in number, shape and size to the exit orifice, or orifices, of said carburetor; an eccentrically pivoted vane in each of said induction passages; first nozzle means communicating with each of said induction passages; second nozzle means communicating with each of said induction passages; first conduit means, for

conveying exhaust gases from the exhaust manifold to said first nozzle means; second conduit means, for conveying atmospheric air to said second nozzle means; first and second tab means, rigidly attached to each of said vanes, for variably obstructing discharge orifices of said first and second nozzle means, respectively; and actuator means, responsive to flow parameters or conditions of gases flowing from said carburetor into said intake manifold through said induction passages, for angularly positioning said vanes with attached tab means, whereby said first and second tab means govern flow of recirculating exhaust gas and dilution air; through said first and said second nozzle means, re-

spectively; into said induction passages. 

1. A device for the reduction of polluting emissions from an internal combustion engine having a carburetor and intake manifold, said device comprising: a body; at least one induction passage through said body, interconnecting said carburetor with said intake manifold; eccentrically pivoted vane means in said induction passage; first and second nozzle means communicating with said induction passages; first conduit means, interconnecting said exhaust manifold of said engine with said first nozzle means; second conduit means, interconnecting said second nozzle means with the atmosphere; first and second tab means, rigidly attached to said vane means, for variably obstructing discharge orifices of said first and second nozzle means, respectively; and actuator means, linked to said vane means, for pivoting same in response to flow parameters or conditions of gases through said induction passage, whereby said first and second tab means govern variable flow of recirculating exhaust gas and atmospheric dilution air through said first and second nozzle means.
 2. The device according to claim 1, wherein said body is provided with a plurality of induction passages, said induction passages being equal in number, and in communication with, multiple induction channels in said carburetor.
 3. The device according to claim 1, wherein saiD actuator means including a positioner sensitive to pressure differential between atmosphere and induction manifold.
 4. The device according to claim 3, wherein said vane means cooperates with said actuator means in positioning said tab means in response to velocity of gases in said induction passage.
 5. The device according to claim 3, wherein said positioner comprises: a hollow chamber; a flexible diaphram partitioning said chamber into first and second spaces; channel means interconnecting said first space with said induction passage; orifice means interconnecting said second space with atmosphere; shaft means, rotatably located in said body, for eccentrically pivoting said vane means; crank means attached to said shaft means; and a link, issuing through said orifice means, interconnecting said diaphram with said crank means, thereby altering angular position of said vane means in response to changes in pressure difference between gases flowing in said induction passage and atmosphere.
 6. The device defined in claim 2, for use with engines equipped with twin-barrel carburetors, wherein said induction passages number two.
 7. The device according to claim 1, wherein said first nozzle means including at least one tubular channel intruding into each of said induction passages, and said second nozzle means including at least one tubular channel intruding into each of said induction passages.
 8. The device according to claim 1, further comprising: third nozzle means communicating with said induction passages; third conduit means, interconnecting said third nozzle means with atmosphere; and governing means, sensitive to differential in pressure between atmosphere and gases flowing through said induction passages, for controlling the flow of additional diluting air into said induction passages.
 9. As an article of commerce, a device for interposition between a carburetor and the intake manifold of an internal combustion engine, said device incorporating means for the reduction of harmful emissions from the exhaust manifold of the engine, comprising; a substantially rectangular body; at least one induction passage through said body, or said passage, or passages, corresponding in number, shape and size to the exit orifice, or orifices, of said carburetor; an eccentrically pivoted vane in each of said induction passages; first nozzle means communicating with each of said induction passages; second nozzle means communicating with each of said induction passages; first conduit means, for conveying exhaust gases from the exhaust manifold to said first nozzle means; second conduit means, for conveying atmospheric air to said second nozzle means; first and second tab means, rigidly attached to each of said vanes, for variably obstructing discharge orifices of said first and second nozzle means, respectively; and actuator means, responsive to flow parameters or conditions of gases flowing from said carburetor into said intake manifold through said induction passages, for angularly positioning said vanes with attached tab means, whereby said first and second tab means govern flow of recirculating exhaust gas and dilution air; through said first and said second nozzle means, respectively; into said induction passages. 